1. Field of the Invention
The present invention relates to a compact testing device for checking for current flow in an electrical circuit. More particularly, the present invention relates to a small, portable, hand-held testing device suitable for testing for current flow, including testing the operational integrity of miniature, plug-in, automotive-type fuses while the fuses are in position in a fuse block.
2. Description of the Related Art
Fuses of the miniature, plug-in type have largely replaced in automobiles the formerly widely used cylindrical glass fuses that were prevalent in the past. Such plug-in fuses are most often found in a unitary fuse block positioned under the dashboard or along the lower, inner side panel in the forward part of the passenger compartment of an automobile for convenient access to all the fuses, to permit simple, rapid removal and replacement of fuses as necessary. Plug-in fuses have a colored plastic housing, and the fuse link, that often is a thin strip of metal having a low melting point, is more difficult to see when the fuse is in its receptacle than was the fuse link in the formerly-used clear glass fuses.
The operational integrity of a fuse is dependent upon whether the fuse link provides a complete electrical connection between the fuse terminals. One way the operational integrity of a plug-in fuse can be determined is by removing the fuse from the fuse block and holding the fuse housing toward a light source to view the fusible link that extends between the fuse terminals, to determine whether the link has melted or separated as a result of the passage through the fuse of an excessively high current. Because of the number of such fuses provided in a modern automobile, the total number of which can easily aggregate about 10 or 12, and because the markings on the fuse block that correspond with the functional circuit in which the fuse is operative are not always entirely clear, determining which of the number of the fuses in the fuse block might have become inoperative could require the removal, visual inspection, and reinstallation of several of the fuses.
Sometimes a continuity checker having a single probe point is utilized, but such a checker must be separately applied to each of the fuse terminals, which requires that two applications of the continuity checker, one application to each of the fuse terminals, be made to test a fuse.
It is an object of the present invention to provide a simple-to-use test device for testing for current flow in an electrical circuit.
It is another object of the present invention to provide a portable, hand-held fuse checker that can be used to check the integrity of a plug-in type fuse without removing the fuse from the fuse block.
It is a further object of the present invention to provide a fuse checker that can be used to test the integrity of a fuse with only a single application of the device to simultaneously check both sides of the fuse without the need to have an operative electrical load connected with the fuse.